Valve Job Mess

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New Member

Hi guys! Been reading here for a long time, and was actually surprised to see that, when I went to post, that I had not actually registered. Corrected.

Forgive me, but I'm actually working on a 225 OF V6 out of a Jeep. Yes, the granddaddy to all the turbo engines. But, I can't think of any other forum where I'd find more knowledgeable guys regarding the Buick V6 than here, so I hope you'll indulge me for a spell.

Bottom end is in pretty good shape, but a busted bolt on the intake and a noisy lifter meant the top end needed to come off. One lifter that was not spinning now means new cam + lifters. OK, I can do that. Since I drive the car a lot, and the top end has never been apart to my knowledge, lets pull the heads and have hardened exhaust seats installed.

Heads off, and delivered to a very highly recommended and respected machine shop here in KC. Said they had done a number of Buick V6's in the past. OK fine. Seemed like nice guys and had some serious and fairly new machines for head work...figured my heads were in the right place.

Two weeks later, I pick them up. Heads are hot tanked and very clean. New stock-type springs installed (Sealed Power), new exhaust valve seats. Valve guides were good. Viton umbrella seal for the exhaust, and a positive seal on the intake. Milled the head about .004" to clean it up. This was a '69 smog motor, but the air pump gave up decades ago and the tubes running to the heads have long since been cut, crimped, and soldered shut. But I did ask them to remove the inner tube section that runs from the machined head fitting to the back side of the exhaust valve. To my dismay, when I got ready to sit down and slap some paint on these in prep for assembly, I saw that they neglected to get those tubes out for me. So, I spent a couple of hours battling them myself and got 'em out. PITA but all is forgiven.

Yesterday, I went to pop the heads on the block after spending hours painting them, and I noticed (yes, for the first time) that the valve retainers were of varying heights. Which here also meant that the height of the valve stem was also varying. I'd throw a bunch of numbers out there, but the bottom line is that I measured (to the best of my ability) the shortest valve stem at 1.917" and the longest was at 1.951", a delta of .034".

While I'm just a shade tree mechanic, I've still done more than a few engines over the years, and on a non-adjustable valve train like the 225 I had always thought that the valve height needed to be kept to about +/-.005 (or .010" from longest to shortest).

I'm fully aware that I may have to have custom pushrods made (do NOT want to use adjustable rods unless there is no other way to get it done). But with a .034" difference between the longest and shortest, proper lifter preload is going to be impossible to achieve.I won't disclose here what I paid to have the work done, but it was a good $100 more than I thought it was gonna be, and certainly ample to have it done right. So, am I out of line (was gonna say 'off my rocker', but naaa) to drag the heads back to the shop and ask about this valve job? Got some machine shop guys here to tell me if my concerns are valid?

(Might add that finding the spec for the installed valve height has been a project in itself. The Kaiser Jeep manual says 1.925",
and 1.930" to 1.970" from the 2006 AERA Engine Builders Association book.)

Member

New Member

Digital caliper with a straight edge across the top of the stem. Thickness of my straight edge subtracted from my final reading.

I do not claim that this is a super-accurate method for measuring stem height, but I'm confident that the difference I have measured from one stem to the next is pretty accurate, and thus the .034" diff between the shortest and longest is valid.

Valve pairs at each cylinder? The worst is a difference of .030" between exhaust and intake of the same cylinder. Still, all are on the same rocker shaft so same cylinder or not, it's a problem (at least the way I see it).

Member

Digital caliper with a straight edge across the top of the stem. Thickness of my straight edge subtracted from my final reading.

I do not claim that this is a super-accurate method for measuring stem height, but I'm confident that the difference I have measured from one stem to the next is pretty accurate, and thus the .034" diff between the shortest and longest is valid. Valve pairs at each cylinder? The worst is a difference of .030" between exhaust and intake of the same cylinder. Still, all are on the same rocker shaft so same cylinder or not, it's a problem (at least the way I see it).

Not taking away from your abilities it sounds like it’s not your first rodeo, but a height mic would be the proper tool to use.
Stupid spell check put “pal” instead of “oal” meaning “over all length” have you taken the valves out and checked the length on both intake and exhaust

New Member

Yes, I know it's not the proper tool, but I'm not a machinist and it's not something I'd be likely to use again (re: spring compressor - seems to have sprouted legs and walked off, but I'm not about to start disassembling the machine shop work and then walk in and complain to them about how the work was done). But please bear with me here...whatever I might end up measuring with the valves out of the head, the fact remains that I have well over .030" difference in height with the valves installed. THIS is the measurement I'm concerned with and it is easily visible by just eyeballing it.

I may need some valves replaced, I may need additional machining of some of the remaining valves and/or seats. I guess what I'm trying to determine is what do the V6 guys DO about valve height and variance from valve to valve. What do you consider acceptable? What should I be saying to the machine shop, if anything?

Member

Hi guys! Been reading here for a long time, and was actually surprised to see that, when I went to post, that I had not actually registered. Corrected.

Forgive me, but I'm actually working on a 225 OF V6 out of a Jeep. Yes, the granddaddy to all the turbo engines. But, I can't think of any other forum where I'd find more knowledgeable guys regarding the Buick V6 than here, so I hope you'll indulge me for a spell.

Bottom end is in pretty good shape, but a busted bolt on the intake and a noisy lifter meant the top end needed to come off. One lifter that was not spinning now means new cam + lifters. OK, I can do that. Since I drive the car a lot, and the top end has never been apart to my knowledge, lets pull the heads and have hardened exhaust seats installed.

Heads off, and delivered to a very highly recommended and respected machine shop here in KC. Said they had done a number of Buick V6's in the past. OK fine. Seemed like nice guys and had some serious and fairly new machines for head work...figured my heads were in the right place.

Two weeks later, I pick them up. Heads are hot tanked and very clean. New stock-type springs installed (Sealed Power), new exhaust valve seats. Valve guides were good. Viton umbrella seal for the exhaust, and a positive seal on the intake. Milled the head about .004" to clean it up. This was a '69 smog motor, but the air pump gave up decades ago and the tubes running to the heads have long since been cut, crimped, and soldered shut. But I did ask them to remove the inner tube section that runs from the machined head fitting to the back side of the exhaust valve. To my dismay, when I got ready to sit down and slap some paint on these in prep for assembly, I saw that they neglected to get those tubes out for me. So, I spent a couple of hours battling them myself and got 'em out. PITA but all is forgiven.

Yesterday, I went to pop the heads on the block after spending hours painting them, and I noticed (yes, for the first time) that the valve retainers were of varying heights. Which here also meant that the height of the valve stem was also varying. I'd throw a bunch of numbers out there, but the bottom line is that I measured (to the best of my ability) the shortest valve stem at 1.917" and the longest was at 1.951", a delta of .034".

While I'm just a shade tree mechanic, I've still done more than a few engines over the years, and on a non-adjustable valve train like the 225 I had always thought that the valve height needed to be kept to about +/-.005 (or .010" from longest to shortest).

I'm fully aware that I may have to have custom pushrods made (do NOT want to use adjustable rods unless there is no other way to get it done). But with a .034" difference between the longest and shortest, proper lifter preload is going to be impossible to achieve.I won't disclose here what I paid to have the work done, but it was a good $100 more than I thought it was gonna be, and certainly ample to have it done right. So, am I out of line (was gonna say 'off my rocker', but naaa) to drag the heads back to the shop and ask about this valve job? Got some machine shop guys here to tell me if my concerns are valid?

(Might add that finding the spec for the installed valve height has been a project in itself. The Kaiser Jeep manual says 1.925",
and 1.930" to 1.970" from the 2006 AERA Engine Builders Association book.)

I understand your frustration, I would hope to see closer numbers for sure. Most machine shops don’t sweat the details, they just try to crank work out the door. Personally i strive for .000 but it doesn’t always happen lol but .004-.006 is acceptable. But I have ocd lol

Active Member

runs with scissors

You didn't say how you arrived at your tip height measurements. If you measured from the seat to the top of a retainer to one valve, then measured all 12 from the retainer to the tip, there's your problem.

You can't measure tip height with a retainer and a spring in the way. If you stacked up a much of iffy measurements, that's a lot of SWAG.

This is the only way to accurately measure tip height.

..and you didn't answer my question... If you lay a straight edge across the TIPS of the valves, are they on the same plane (plus or minus a few thou). Patching up a set of old ass heads can leave retainer heights all over the place, yet the tips can (should) be ground to compensate for sinking seats, and ground valve faces.

These heads I built last weekend had the exhaust tips .030" higher than the intakes. These castings were beat to hell so the exhaust seats were sunk a little and I installed O/S intake valves that stuck into the combustion chamber a little more than normal. I'm a HS dealer so I'll be running adjustable rockers and don't care about the difference at the moment. Until I get the valvetrain mocked up, I have no idea what pushrod length I need or if I'm going to lower the shaft pedestals on the mill.

New Member

The machined valve seat surface extends beyond the diameter of the retainer just enough to get the tail end of a caliper to make a reliable measurement from there to the top of a straight edge laid on top of the valve. Straight edge is .060" thick, so that is subtracted from my measurement to arrive at the final figure.

No. Not even close. The difference in stem height corresponds to the measurements I posted above.

I get that this is an unacceptable method to measure stem height from a machine shop standpoint, but I have applied due diligence to the degree that the difference in stem height that I'm measuring from one valve to another is valid.

Active Member

The machined valve seat surface extends beyond the diameter of the retainer just enough to get the tail end of a caliper to make a reliable measurement from there to the top of a straight edge laid on top of the valve. Straight edge is .060" thick, so that is subtracted from my measurement to arrive at the final figure.
No. Not even close. The difference in stem height corresponds to the measurements I posted above.

I get that this is an unacceptable method to measure stem height from a machine shop standpoint, but I have applied due diligence to the degree that the difference in stem height that I'm measuring from one valve to another is valid.Yes...the point I've been focused on. What's acceptable? How to address this with the machine shop?

I'll check it out. Edit: My engine is a good 20 years older than that. Is there something specifically that you wanted me to look at?

New Member

Oops...guess I didn't read carefully enough. Still, looks like that '87 head wants longer valves than my '69. As I put in the first post:

Kaiser Jeep FSM spec: 1.925" (I'm assuming that that is an absolute minimum usable length)
2006 AERA Engine Builders Association book: 1.930" to 1.970" (I'm assuming that this is the usable range, but still, no spec is given for an acceptable variance, so I'm sticking with my +/-.005" till further notice)

runs with scissors

Based on that, you're assUming that GN 8445 spring pockets are at the same height relative to the valve seat as your Kaiser castings. And I have no idea if that's the case. You have to either have the two heads next to each other with some precision measuring equipment, a pair of factory prints, and/or verify the OAL of both valves are the same. And if they aren't, what's the difference? And it's possible they're both different.

That being said, if you have non-adjustable shaft rocker like we do, your valve tips really need to be pretty close to each other. Keep in mind, you divide the delta by 1.55 to find the difference in actual lifter preload. It's not exact, as our actual rocker ratios aren't accurate or consistant.

New Member

As a followup, the shop told me that the spring seats in several locations were about 0.030" lower than the others and probably grenaded their measurements. Regardless, the end result was a range of stem heights that were going to be a problem. Solution? New exhaust valves, and grind them so they match the intakes. They were apologetic, but I had to buy the new valves (so, not THAT apologetic). I just picked up the heads yesterday, and a cursory look indicates that they are likely OK...need to do more work but it's awfully damn cold out in the garage right now.

runs with scissors

That makes no sense. IF the seats are sunk .030" that moves the installed height and tip high up .030". The only way to get that number down is to replace the seats, or tip the valves .030".

Buying a new seat of valves with the same OAL, will still have you .030" tall. (or more if your original valves had been tipped in the past). And if you grind the crap out of the valve face, that will make the tip height even taller.